In anime that were adapted from a manga, if it follows the manga, it would either follow it faithfully (Fullmetal Alchemist Brotherhood) or deviate from the manga's plot line (Oran High School Host Club, Original Fullmetal Alchemist). In my experience, anime deviations from manga normally occur because the manga is still ongoing and original filler is not enough.
Given how both the Naruto anime and manga are still ongoing, I am wondering if the anime of Naruto has deviated from the manga to the point where it could break continuity with the manga
For example, the 2003 Fullmetal Alchemist anime breaks continuity:
at Laboratory 5 or when we learn who Sloth and Wrath are